1. Field of the Invention
This invention relates to up-conversion of digital video signals from a conventional format to a high-definition format.
2. Description of the Prior Art
High definition digital video is becoming increasingly popular, and common formats for the video signals are:
SMPTE 240 M format, which is characterised by 1125 lines, 60 field/s, 2:1 interlace, with a 16:9 aspect ratio and 1920.times.1035 active pixels per frame; and PA1 European HDTV format, which is characterised by 1250 lines, 50 field/s, 2:1 interlace, with a 16:9 aspect ratio and 1920.times.1152 active pixels per frame. PA1 CCIR 601 525-line format, which is characterised by 525 lines, 60 field/s, 2:1 interlace, with a 4:3 aspect ratio and 720 .times.486 active pixels per frame; PA1 CCIR 601 625-line format, which is characterised by 625 lines, 50 field/s, 2:1 interlace, with a 4:3 aspect ratio and 720 .times.576 active pixels per frame; PA1 4fsc 525 D2 format, which is characterised by 525 lines, 60 field/s, 2:1 interlace, with a 4:3 aspect ratio and 768.times.486 active pixels per frame; and PA1 4fsc 625 D2 format, which is characterised by 625 lines, 60 field/s, 2:1 interlace, with a 4:3 aspect ratio and 948.times.576 active pixels per frame.
More and more material is being originated in these formats for processing and/or distribution in them. However, there is obviously a great bulk of material which has been originated, or still needs to be originated, in conventional definition format, and there is a desirability to be able to up-convert such material to high definition format so that it can be integrated with other high definition material and/or so that it can be distributed in high definition format. Examples of conventional definition digital formats are:
Problems associated with such up-conversion include dealing with the change of aspect ratio from 4:3 to 16:9, in addition to dealing with the changes of resolution, which are different in the horizontal and vertical directions, and providing temporal conversion in the case of a change in field rate.